Distal protection device

ABSTRACT

A distal protection device comprising a catheter having a first strut movable from a collapsed configuration to an expanded configuration having a first dimension and a second strut movable from a collapsed configuration to an expanded configuration having a second dimension larger than the first dimension. Movement of the first strut deploys filter material to a first position having a first deployed dimension and movement of the second strut to a first position deploys filter material to a second deployed dimension larger than the first expanded dimension.

This application claims priority from U.S. provisional application Ser.No. 60/466,491, filed Apr. 29, 2003, the entire contents of which areincorporated herein by reference.

BACKGROUND

1. Technical Field

This application relates to a vascular device and more particularly to avascular device for capturing embolic material during surgicalprocedures.

2. Background of Related Art

During vascular surgical procedures such as stenting, angioplasty,thrombectomy, and atherectomy, embolic material such as plaque and bloodclots can become dislodged. Dislodgement of such embolic material cancause the emboli to flow downstream to lodge in the vascular system,thereby occluding the flow of oxygenated blood to the brain or othervital organs. Such occlusion can compromise peripheral circulationresulting in amputation, or result in heart attack, stroke or evendeath.

Techniques to cut the debris into smaller sizes, such as by use oflasers, have had significant drawbacks, such as the inability to ensureall the debris is cut into sufficiently small fragments. If some of thefragments remain too large, then occlusion of the vessels can occurcausing the problems and risks enumerated above.

Attempts have been made to place a device distal (downstream) of thestenosis, thrombus, etc. to capture the emboli. Such distal protectiondevices typically are collapsible for insertion and expandable once inthe vessel. Some devices are in the form of an expandable balloon whichis inserted within the vessel inside a sheath. When the sheath iswithdrawn, the balloon is expanded to block emboli. These balloondevices even in the collapsed position increase the profile of thedevice since they are wrapped on the outside of the device. In otherdistal protection devices, a wire is covered by a membrane. These wiresextend laterally from the device and may not enable the membrane toblock the entire region of the vessel. Failure to expand to a geometryto block the entire region can result in the unwanted passage of debriswhich can cause vessel occlusion and the aforementioned adverseconsequences.

The need therefore exists for an improved distal protection device. Suchdevice would have a reduced profile to facilitate insertion and tobetter enable placement of the device distal of the emboli to blockpotential downstream flow. The device would also be easy to manipulateand sufficiently fill the vessel area to ensure all passage is blocked.The device would further be configured to avoid unwanted collapse duringuse.

It would also be desirable to provide a distal protection device whichmeets the above criteria plus has the advantage of accommodating varioussized blood vessels. There is a tradeoff between providing largeexpansion of a distal protection device to block large blood vesselswhile ensuring that such large expansion would not damage a small bloodvessel. Therefore, it would be advantageous to provide a single devicewhich can expand sufficiently to effectively block embolic materialwithout damaging the vessel, thus avoiding having to use differentdevices to accommodate different vessel sizes.

SUMMARY

The present invention overcomes the problems and deficiencies of theprior art. The present invention provides a distal protection devicecomprising a catheter having a first strut movable from a collapsedconfiguration to an expanded configuration and a second strut axiallyspaced from the first strut and movable from a collapsed configurationto an expanded configuration. The first strut has a first dimension andthe second strut has a second dimension larger than the first dimension.The first and second struts are separately deployable. Movement of thefirst strut deploys filtering material to a first position having afirst deployed dimension and movement of the second strut to a firstposition deploys filtering material to a second deployed dimensionlarger than the first deployed dimension.

In one embodiment, the same filtering material overlies both the firstand second strut. In another embodiment, separate filtering materialsoverly the first strut and the second strut, but preferably the sametype of material. In one embodiment, the material is a wire braidcomposed of a shape memory metal.

In one embodiment, the first strut is positioned proximal of the secondstrut. In another embodiment, the first strut is positioned distal ofthe second strut. Preferably, the struts are formed from a laser cuttube.

Preferably, the first and second struts are deployed laterally of thecatheter and each form loops opening in a direction substantiallyaligned with blood flow such that the plane of the loop opening issubstantially transverse to the direction of blood flow andsubstantially parallel to a transverse axis of the catheter.

The device may further comprise an actuating member slidably positionedwithin the catheter such that initial movement initially moves eitherthe first strut or second strut from the collapsed position to theexpanded configuration to form a loop. In a preferred embodiment,further movement of the actuating member moves the remaining collapsedstrut to the expanded configuration to also form a loop.

The present invention also provides a distal protection devicecomprising a tube having a plurality of cutouts forming at least onedistal elongated strut and at least one proximal elongated strut. Thestruts are movable from a retracted (collapsed) to an expanded position.Filter material overlies at least a portion of the struts and anactuating member is operatively connected to a portion of the tubewherein movement of the actuating member moves the portion of the tubeto thereby move the distal elongated strut and the proximal elongatedstrut to the expanded position.

In a preferred embodiment, movement of the actuating member in a firstdirection retracts the portion of the tube to compress and therebyexpand the elongated struts and movement of the actuating member in areverse direction advances the portion of the tube to move the elongatedstrut to the retracted position.

In one embodiment the distal elongated strut(s) has a length greaterthan a length of the proximal elongated strut(s) such that uponexpansion the distal elongated strut expands to a transverse dimensiongreater than a transverse dimension of the proximal strut. In anotherembodiment, the distal elongated strut(s) has a length smaller than alength of the proximal elongated strut(s) such that upon expansion thedistal elongated strut expands to a transverse dimension smaller than atransverse dimension of the proximal strut.

In one embodiment, the filter material comprises a first materialpositioned over the distal elongated strut(s) and a separate material,preferably of the same composition (type), positioned over the proximalelongated strut(s). In another embodiment, the filter material overliesboth the distal and proximal elongated struts. In one embodiment, thefilter material comprises a wire braid composed of a shape memorymaterial. In one embodiment, the filter material automatically movesback from an expanded position to a collapsed position upon movement ofthe at least one strut to the retracted position.

Preferably, the elongated struts form loops having a loop opening lyingin a plane substantially transverse to a longitudinal axis of the tubeand substantially parallel to a transverse axis of the tube.

The present invention also provides a distal protection devicecomprising a catheter having a tube formed with cutouts therein to forma first set of elongated struts and a second set of elongated struts.The elongated struts are movable between a retracted (collapsed)position and an expanded position wherein the distance between theproximal end and distal end of the struts in the retracted position is afirst distance and the distance between the proximal end and distal endof the struts in the expanded position is a second distance less thanthe first distance. In the expanded position, the struts form loops withan opening lying in a plane substantially parallel to a transverse axisof the catheter and substantially transverse to the direction of bloodflow. Filter material is deployable by the loops of the struts. Thefirst set of struts is separately movable from the second set of strutsto the expanded position to enable selective actuation of the set ofstruts to accommodate different sized vessels.

In one embodiment, the first set of elongated struts has a smallerbuckling force than the second set of elongated struts such that uponactuation of an actuating member, the first set of elongated strutsbuckles fully to its expanded position and upon further actuation, thesecond set of elongated struts buckles fully to its expanded position.

In one embodiment, the tube forms first and second collars, and anactuating member is connected to the second collar such that theactuating member retracts the second collar to compress and therebyexpand the elongated struts, and the first collar further acts as astop.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described hereinwith reference to the drawings wherein:

FIG. 1 is a perspective view of a first embodiment of the distalprotection device of the present invention in the collapsed position(the filtering material is removed for clarity);

FIG. 1A is an exploded view of the device of FIG. 1 (the filteringmaterial is removed for clarity);

FIG. 1B is an enlarged view of a distal portion of the device of FIG. 1;

FIG. 2 is a transverse cross-sectional view taken along lines 2-2 ofFIG. 1;

FIG. 3 is a transverse cross-sectional view taken along lines 3-3 ofFIG. 1;

FIG. 3A is a longitudinal cross-sectional view of the device of FIG. 1in the collapsed position;

FIG. 3B is a longitudinal cross-sectional view of the device of FIG. 1showing the first set of struts and filtering material in an expandedposition;

FIG. 4 is a perspective view of the distal portion of the distalprotection device of FIG. 1 showing the first set of struts and firstcapturing (filtering) element (material) partially expanded;

FIG. 5 is a view similar to FIG. 4 showing the first set of struts andcapturing element almost fully expanded;

FIG. 5A is a front view of the device of FIG. 5;

FIG. 6 is a view similar to FIG. 4 showing the first set of struts andfirst capturing element fully expanded and the second set of struts andsecond capturing (filtering) element (material) partially expanded;

FIG. 7 is a view similar to FIG. 4 showing the first and second sets ofstruts and first and second capturing elements fully expanded;

FIG. 8 is a view similar to FIG. 7, (both sets of struts expanded)except showing an alternate embodiment having a single capturing(filtering) element (material);

FIG. 9 is a perspective view of the distal portion of the distalprotection device showing an alternate embodiment wherein the smallercapturing element is positioned distal of the larger capturing element;

FIG. 10 is a view similar to FIG. 9 showing an alternate embodimenthaving a single capturing element expandable by the first and secondsets of struts;

FIG. 11A is a view similar to FIG. 7 showing an alternate embodiment ofthe capturing elements composed of a wire braid;

FIG. 11B is a perspective view of an alternate embodiment of the distalprotection device having first and second sets of struts of differentconfiguration, and shown in the collapsed configuration (the filteringmaterial is removed for clarity);

FIGS. 11C and 11D are transverse cross-sectional views taken along lines11C and 11D, respectively, of FIG. 11B; and

FIGS. 12 and 13 illustrate placement of the device of FIG. 1, whereinFIG. 12 shows the catheter advanced through the femoral to the carotidartery and FIG. 13 shows the device deployed in the carotid artery toblock distal flow of emboli.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawings where like reference numeralsidentify similar or like components throughout the several views,several different embodiments for capturing embolic material duringsurgical procedures are disclosed. In each of the embodiments, twofiltering devices are provided, with each filtering device designed toblock embolic material while maintaining blood flow therethrough. Thefiltering devices are deployable to different transverse dimensions toaccommodate different size vessels as described in more detail below.

Turning first to the embodiment illustrated in FIGS. 1-7, the distalprotection device 10 includes a catheter having an outer tube 11, aninternal coupler 14, a distal tube 16, a first capturing element 50 anda second capturing element 60. The capturing (filtering) elements 50 and60 are movable between collapsed and expanded positions by struts 32,34, respectively, formed in tube 16. As shown in FIGS. 3-7, firstcapturing element 50 is positioned proximally of second capturingelement 60. As will be explained in further detail below, the capturingelements 50, 60 expand to different diameters to accommodate differentsized vessels. The struts 32, 34 are formed so that relative movement ofportions of the tube 16 expands the struts 32, 34. That is, an actuatingmember such as a shaft or wire 22 is slidably positioned within outertube 11 and attached to a distal portion of tube 16. When actuating wire22 is retracted, it moves a portion of the distal tube 16 proximally toexpand the struts 32, 34, as explained in more detail below. Coupler 14connects the tube 16 to the outer tube 11. The proximal end of coupler14 is bonded, glued or attached by other means inside the outer tube 11.The distal tube 16 is slid over the coupler 14 and bonded or glued (orotherwise attached) thereto.

Turning to the distal tube 16, the struts 32, 34 are preferably formedby elongated slots or cutouts 37, 38, respectively, in the tube 16 (seee.g. FIGS. 1 and 1A). These slots 37, 38 are preferably formed by lasercutting the tube 16 although other ways to cut the slots are alsocontemplated. As formed, the slots 37, and therefore the struts 32, havea smaller length than the length of the slots 38 and struts 34. In oneembodiment, in the collapsed position, the length L1 of the struts 32 isabout 10 mm and the length L2 of the struts 34 is about 20 mm. Otherdimensions are also contemplated.

The distal tube 16 is formed so that a first collar 40 is at theterminal end 33 of struts 32 and a second collar 42 is at the terminalend 43 of struts 34 (see FIGS. 1 and 1A). Thus, struts 32 extend fromproximal tube end 17 to first collar 40 and the second longer struts 34extend from first collar 40 to second collar 42 at the end of tube 16.

A radiopaque tip 27 is attached, e.g. by soldering, to the second ordistal collar 42. This tip 27 guides the catheter and enables imaging ofthe catheter.

Inner actuating shaft or wire 22 is positioned within the outer tube 11and is connected at its distal end to the collar 42 of distal tube 16.The proximal end 17 of the tube 16 can be fixed to tube 11 and/orcoupler 14. Thus, sliding movement of the actuating wire 22 slides thecollars 40, 42 proximally to compress the struts 32, 34. That is, uponproximal movement of the actuating wire 22 in the direction of the arrowof FIG. 4, the collars 40, 42 move proximally, thus forcing struts 32and 34 outwardly as shown in FIGS. 4-7. Initially, upon retraction ofwire 22, struts 32 will buckle first as shown in FIG. 5 since due totheir reduced length the buckling force is less than the buckling forceof the longer struts 34. The struts 32 will continue to buckle until theproximal surface 49 of collar 40 abuts the distal surface 15 of coupler14. (See FIG. 5 which shows almost complete expansion of the struts 32,the remaining expansion corresponding to the remaining distance betweenproximal surface 49 and distal surface 15). Thus, coupler 14 (or collar40) acts as a stop.

To further lower the buckling force, the shorter struts could be madethinner than the longer struts, such as shown for example in FIGS. 11B,11C, and 11D, wherein struts 32″ have a diameter less than the diameteror thickness of the longer struts 34″ of device 10″.

The buckling forces can also be changed by modifying the resistance ofmovement of the respective collars.

Referring to FIG. 6, after struts 32 buckle, further proximal movementof actuating wire 22 continues to move collar 42 as movement of collar40 is stopped by abutment with coupler 14. That is, since proximalmovement of collar 40 at this point is stopped by abutment of collar 40with the surface 15 of inner coupler 14, further proximal movement willfurther retract only collar 42, causing longer struts 34 to buckleoutwardly to their fully expanded position shown in FIG. 7. Thus, thereduction of the distance between the collars 40, 42 forces the strutsto compress and extend radially outwardly as shown in FIG. 7.

The expansion movement of the struts 32, 34 causes the overlying filtermaterial 50, 60 to be deployed, moving to an expanded position. Asshown, the filter material 50, 60 can be a polymeric membrane, such aspolyurethane or PET, which is expanded by the struts 32, 34. A mouth oropening 52, 62 (see FIGS. 4 and 6) is provided at the proximal end ofthe filter material The polymeric material would have small holesdimensioned for allowing blood flow while blocking embolic material.Thus, embolic material exceeding a certain size carried by the blood iscaptured with smaller particles flowing through the holes or pores inthe membrane. Alternatively, as shown in FIG. 11A, the filter of device110 can be a tightly wound metal braided material such as shape memorymetal, e.g. Nitinol. Thus, braided filtering material 150 overliesstruts 132 and braided filtering material 160 overlies struts 134. Thefiltering material 150, 160 can also include a mouth or opening.Actuating member 122 moves the collars 140, 142 in the same manner asactuating member 22 of FIG. 1.

Preferably, the filtering material will be selected so that after it isradially stretched to an expanded configuration to block and captureflow of embolic material, it automatically retracts once the struts 32,34 are moved to their collapsed position, as described in more detailbelow. In one embodiment, such as shown in the embodiments of FIGS. 1-7,a first filter material overlies struts 32 and a separate second filtermaterial overlies struts 34. The separate material is preferably of thesame type of material, however alternately it could be composed of adifferent material. In an alternate embodiment, shown in FIG. 8, ratherthan two separate filters, a single filtering material 64 is provided.One portion 65 of filter material 64 overlies struts 34 in its entiretywhile portion 63 overlies only a portion of struts 32, leaving anopening 67. Similarly, in the embodiment of the braided material, twoseparate elements can be provided as in FIG. 11A or alternatively asingle filtering element could be provided overlying both sets ofstruts.

Referring back to the struts 32, 34, in the initial collapsedconfiguration, struts 32 and 34 are aligned with the outer surface ofthe distal tube 16 (and collars 40, 42) which is aligned with outer tube11 to enable smooth insertion into the vessel and keep the overallinsertion profile at a minimum. Proximal struts 32, when moved from acollapsed (retracted) position to an extended (expanded) position, eachform a looped configuration, the loops designated by reference numeral38. Thus, the struts 32 are forced out laterally to bend into a loop 38(see FIG. 5). End 47A extends proximally and end 47B extends distally.The expanded loop 38 thus, has an opening 39 preferably lying in a planesubstantially perpendicular to the longitudinal axis and substantiallyparallel to the transverse axis of the catheter. That is, the loopopening 39 lies in a plane substantially transverse to the direction ofblood flow so the loop opening is substantially in line with the bloodflow. In one embodiment, the loop opening plane can be at 90 degrees tothe longitudinal axis. In another embodiment, it can be offset so it isat angle of less than 90 degrees, but preferably greater than about 45degrees. In such embodiment, each strut 32 extends such that the loopopening 39 is slightly offset from the direction of the transverse axisof the catheter (and tube 16) but is still open generally in thedirection of blood flow (for example, a 60 degree angle). Thus, in thisembodiment, a central longitudinal axis extending through the loopopening could be at a small angle rather than parallel to thelongitudinal axis of the tube 16, preferably less than 45 degrees tomaintain the opening substantially in the direction of blood flow.

The formation of the loop stretches the membrane or filtering element toblock the flow of material. In the membrane or braid, windows can beprovided with enlarged openings for blood flow, with the membrane orbraid blocking flow of materials exceeding the pore size. Alternatively,the material can have an open mouth region as illustrated and describedabove.

The shorter struts 32 preferably form two looped regions 39 whenexpanded so the filter material stretches in two directions. Whenslidable wire 22 is retracted in the direction of the arrow of FIG. 4 sothe struts 32 buckle as described above, two looped regions are formed,one on one side of the catheter and the second looped wire region on theother side of the catheter, preferably about 180 degrees apart asdepicted in FIG. 5. This double looped configuration causes the filtermaterial to be expanded on opposing sides of the tube 16 and preferablyblocking a 360 degree area. Although two struts 32 are shown, morestruts 32 could be provided. Also, alternatively a single strut could beprovided.

The second longer struts 34 form four looped regions 41 when expandedsince four struts 34 are provided. When slidable wire 22, is retractedin the direction of the arrow and the struts 34 buckle as describedabove, four looped regions are formed, preferably about 90 degreesapart, causing filter material to be expanded radically on multiplesides of the tube 16 as illustrated in FIG. 7 and preferably blocking a360 degree area. As in the loops of struts 32, the loops 38 opengenerally in a direction of blood flow, with the openings in the loopbeing substantially parallel to the transverse axis of the tube 16, andthe loop opening plane being substantially perpendicular to thelongitudinal axis and transverse to the direction of blood flow. As inloops 39, the plane of the opening of loop 38 in one embodiment is 90degrees with respect to the longitudinal axis and parallel to thetransverse axis. In another embodiment it is offset to form an angle ofless than 90 degrees, but preferably greater than 45 degrees. Althoughfour loops are shown, fewer or greater number of struts could beutilized.

In the alternate embodiments of FIGS. 9 and 10, the distal protectiondevice 210 has shorter length struts distal of the larger struts. Morespecifically, referring first to FIG. 9, distal protection device 210has two elongated struts 232 positioned distal of elongated struts 234.Actuating wire or shaft 222 is pulled proximally to retract collars 242,240 to expand the respective struts 232, 234. Struts 232 buckle first,followed by buckling of longer struts 234.

Filtering material 250 overlying struts 232 is expanded to a smallerdimension than filtering material 260 overlying struts 234. In thealternate embodiment of FIG. 10, instead of the separate filteringmaterials, a single filtering material 270 overlies struts 232′ and 234′of distal protection device 210′. Otherwise the embodiment of FIGS. 9and 10 are the same and corresponding parts are designated “prime”.Alternatively, both sets of struts can begin to buckle simultaneously,or the longer struts can begin to buckle first, followed by additionalexpansion of the shorter struts first. The longer struts, however, wouldnot fully expand until the shorter struts fully expand.

In the preferred embodiment, the catheter has a length of about 135 cmto about 300 cm. The diameter of the catheter is preferably about 0.010inches to about 0.030 inches and more preferably about 0.018 inches toenable low profile insertion into the vessel. The first capturingelement 50, when expanded, preferably has a diameter from about 1 mm toabout 4 mm. The second capturing element 60, when expanded, preferablyhas a diameter from about 4 mm to about 9 mm.

In use, if the vessel is a smaller size, e.g., 2 mm, only the smallercapturing element 50 would be deployed. If the vessel is a larger size,after deployment of the first capturing element 50, the second capturingelement 60 would be deployed in the manner described above.

To withdraw the device 10, the actuating wire 22 is pushed distally toadvance collars 40, 42 to retract the loops as the struts 32, 34 returnto their collapsed positions to enable the filter material to return tothe initial low profile collapsed insertion position. In a preferredembodiment, the filter is made of a material that would returnautomatically from its stretched position to the original collapsedposition when the wire 22 is pushed distally. One way this could beachieved is by use of the shape memory material with a memorizedposition in the collapsed position. This passive self-contraction wouldavoid the need for insertion of a separate device or sheath over thefilter material to cover it for removal, thus reducing the overallprofile of the instrumentation necessary for the procedure. That is, inthe preferred embodiment, the wire 22 and thus the struts 32, 34 areexpanded by active control while the filter material would automaticallyretract without other assistance.

In another embodiment, the filter material can be attached to the struts32, 34 and thereby move with the actuating wire 22 between the collapsedand expanded positions.

Being part of a guidewire, in use, the distal protection devicesdescribed herein, can be used for initial introduction of a catheter.The distal protection device could also be placed within a catheterafter the guidewire for introducing the catheter is withdrawn. Thecatheter can then be withdrawn and another catheter, such as a stentdelivery catheter, could be inserted over the distal protection device.As other catheters can be inserted over the device, it further functionsas a guidewire.

FIGS. 12-13 show the positioning of the distal protection device 10 ofthe present invention in a larger vessel when deployment of the largerstruts is desirable. These Figures show the device 10 inserted by way ofexample, as the other devices described herein can be inserted andplaced in a similar manner. Device 10 of FIG. 1 is shown deployed in thecarotid artery “c”. The introducer is inserted through the femoral vein“f” as shown in FIG. 12. The device 10 is advanced through the femoralvein to the carotid artery “c”. Once positioned at the desired site, theactuating wire is retracted as described above to deploy both sets ofstruts 32, 34 to the looped configuration to expand the filter material50 and larger filter material 60 to block emboli in the artery.

It should be appreciated that the terms “first and second” as usedherein are used for the readers' convenience. Also, proximal refers tothe region closer to the user and distal to the region further from theuser, again used for the readers' convenience.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Forexample, different filter materials can be utilized such as polymericmaterial, a composite of a polymeric material and metallic material ormetal fibers, an elastomeric material, or a composite of elastomeric andmetallic material. (Examples of polymeric material include polyester,PET, LDPE (low density polyethylene), HDPE; examples of elastomericmaterial include silicon and urethane; examples of metallic materialsinclude stainless steel and shape memory Nitinol). Those skilled in theart will envision many other possible variations that are within thescope and spirit of the disclosure as defined by the claims appendedhereto.

1-23. (canceled)
 24. A distal protection device comprising a elongatedmember having a longitudinal axis and first and second capturingelements movable with respect to the elongated member from a collapsedposition to an expanded position, the first capturing element having afirst transverse dimension in the expanded position and the secondcapturing element having a second greater transverse dimension in theexpanded position, an actuating member movable to move the first andsecond capturing elements to the expanded position, the first and secondcapturing elements being separately deployable.
 25. The device of claim24, wherein the second capturing element is distal of the firstcapturing element.
 26. The device of claim 25, wherein the secondcapturing element is proximal of the first capturing element.
 27. Thedevice of claim 25, wherein the first capturing element is deployedprior to deployment of the second capturing element.
 28. The device ofclaim 24, wherein the actuating member is attached to a collar, andmovement of the collar moves the first and second capturing elements tothe expanded position.
 29. The device of claim 24, wherein the actuatingmember is slidable proximally to move the first and second capturingelements to the expanded position and slidable distally to move thefirst and second capturing elements to the collapsed position.
 30. Thedevice of claim 25, wherein the first capturing element has a firstbuckling force lower than a second buckling force of the secondcapturing element.
 31. The device of claim 27, further comprising a stopfor the first capturing element, wherein contact with the stopsubsequently enables the second capturing element to move to the secondexpanded position.
 32. The device of claim 24, wherein in the collapsedposition the second capturing element has a length greater than a lengthof the first capturing element.
 33. The device of claim 24, wherein inthe collapsed position, the first and second capturing elements arealigned with an outer surface of the elongated member.
 34. The device ofclaim 24, wherein the capturing elements include a polymeric membrane.35. The device of claim 24, further comprising a first collar and asecond collar, the first collar being positioned distal of the secondcollar, the first and second collars movable by the actuating member tomove the first and second capturing elements to the expanded position.36. The device of claim 24, wherein the first and second capturingelements include a braided material.
 37. The device of claim 24, whereinin the collapsed position, the first and second capturing elements arealigned with an outer surface of the elongated member.